-
The ARGO-YBJ Collaboration,
B. Bartoli,
P. Bernardini,
X. J. Bi,
I. Bolognino,
P. Branchini,
A. Budano,
A. K. Calabrese Melcarne,
P. Camarri,
Z. Cao, [......],
P. Zhang,
X. Y. Zhang,
Y. Zhang,
J. Zhao,
Zhaxiciren,
Zhaxisangzhu,
X. X. Zhou,
F. R. Zhu,
Q. Q. Zhu,
G. Zizzi
[show abstract]
[hide abstract]
ABSTRACT: We report the observation of a very high energy \gamma-ray source, whose
position is coincident with HESS J1841-055. This source has been observed for
4.5 years by the ARGO-YBJ experiment from November 2007 to July 2012. Its
emission is detected with a statistical significance of 5.3 standard
deviations. Parameterizing the source shape with a two-dimensional Gaussian
function we estimate an extension \sigma=(0.40(+0.32,-0.22}) degree, consistent
with the HESS measurement. The observed energy spectrum is dN/dE =(9.0-+1.6) x
10^{-13}(E/5 TeV)^{-2.32-+0.23} photons cm^{-2} s^{-1} TeV^{-1}, in the energy
range 0.9-50 TeV. The integral \gamma-ray flux above 1 TeV is 1.3-+0.4 Crab
units, which is 3.2-+1.0 times the flux derived by HESS. The differences in the
flux determination between HESS and ARGO-YBJ, and possible counterparts at
other wavelengths are discussed.
03/2013;
-
The ARGO-YBJ Collaboration,
B. Bartoli,
P. Bernardini,
X. J. Bi,
C. Bleve,
I. Bolognino,
P. Branchini,
A. Budano,
A. K. Calabrese Melcarne,
P. Camarri, [......],
P. Zhang,
X. Y. Zhang,
Y. Zhang,
J. Zhao,
Zhaxiciren,
Zhaxisangzhu,
X. X. Zhou,
F. R. Zhu,
Q. Q. Zhu,
G. Zizzi
[show abstract]
[hide abstract]
ABSTRACT: As one of the brightest active blazars in both X-ray and very high energy
$\gamma$-ray bands, Mrk 501 is very useful for physics associated with jets
from AGNs. The ARGO-YBJ experiment is monitoring it for $\gamma$-rays above 0.3
TeV since November 2007. Starting from October 2011 the largest flare since
2005 is observed, which lasts to about April 2012. In this paper, a detailed
analysis is reported. During the brightest $\gamma$-rays flaring episodes from
October 17 to November 22, 2011, an excess of the event rate over 6 $\sigma$ is
detected by ARGO-YBJ in the direction of Mrk 501, corresponding to an increase
of the $\gamma$-ray flux above 1 TeV by a factor of 6.6$\pm$2.2 from its steady
emission. In particular, the $\gamma$-ray flux above 8 TeV is detected with a
significance better than 4 $\sigma$. Based on time-dependent synchrotron
self-Compton (SSC) processes, the broad-band energy spectrum is interpreted as
the emission from an electron energy distribution parameterized with a single
power-law function with an exponential cutoff at its high energy end. The
average spectral energy distribution for the steady emission is well described
by this simple one-zone SSC model. However, the detection of $\gamma$-rays
above 8 TeV during the flare challenges this model due to the hardness of the
spectra. Correlations between X-rays and $\gamma$-rays are also investigated.
09/2012;
-
B. Bartoli,
P. Bernardini,
X. J. Bi,
C. Bleve,
I. Bolognino,
P. Branchini,
A. Budano,
A. K. Calabrese Melcarne,
P. Camarri,
Z. Cao, [......],
L. Zhang,
P. Zhang,
X. Y. Zhang,
Y. Zhang,
Zhaxiciren,
Zhaxisangzhu,
X. X. Zhou,
F. R. Zhu,
Q. Q. Zhu,
G. Zizzi
[show abstract]
[hide abstract]
ABSTRACT: The ARGO-YBJ experiment detects extensive air showers in a wide energy range by means of a full-coverage detector which is in stable data taking in its full configuration since November 2007 at the YBJ International Cosmic Ray Observatory (4300 m a.s.l., Tibet, People’s Republic of China). In this paper the measurement of the light-component spectrum of primary cosmic rays in the energy region (5÷200) TeV is reported. The method exploited to analyze the experimental data is based on a Bayesian procedure. The measured intensities of the light component are consistent with the recent CREAM results and higher than that obtained adding the proton and helium spectra reported by the RUNJOB experiment.
Phys. Rev. D. 05/2012; 85(9).
-
H W Zhao,
W Lu,
X Z Zhang,
Y C Feng,
J W Guo,
Y Cao, J Y Li,
X H Guo,
S Sha,
L T Sun,
D Z Xie
[show abstract]
[hide abstract]
ABSTRACT: SECRAL (superconducting ECR ion source with advanced design in Lanzhou) ion source has been in routine operation for Heavy Ion Research Facility in Lanzhou (HIRFL) accelerator complex since May 2007. To further enhance the SECRAL performance in order to satisfy the increasing demand for intensive highly charged ion beams, 3-5 kW high power 24 GHz single frequency and 24 GHz +18 GHz double frequency with an aluminum plasma chamber were tested, and some exciting results were produced with quite a few new record highly charged ion beam intensities, such as (129)Xe(35+) of 64 eμA, (129)Xe(42+) of 3 eμA, (209)Bi(41+) of 50 eμA, (209)Bi(50+) of 4.3 eμA and (209)Bi(54+) of 0.2 eμA. In most cases SECRAL is operated at 18 GHz to deliver highly charged heavy ion beams for the HIRFL accelerator, only for those very high charge states and very heavy ion beams such as (209)Bi(36+) and (209)Bi(41+), SECRAL has been operated at 24 GHz. The total operation beam time provided by SECRAL up to July 2011 has exceeded 7720 hours. In this paper, the latest performance, development, and operation status of SECRAL ion source are presented. The latest results and reliable long-term operation for the HIRFL accelerator have demonstrated that SECRAL performance for production of highly charged heavy ion beams remains improving at higher RF power with optimized tuning.
The Review of scientific instruments 02/2012; 83(2):02A320. · 1.52 Impact Factor
-
W H Zhang,
H Y Ma,
Y Yang,
Q Wu,
X Z Zhang,
H Wang,
B H Ma,
Y C Feng,
X Fang,
J W Guo, [......],
S Sha,
W Lu,
S H Lin,
X H Guo,
H Y Zhao,
L T Sun,
D Z Xie,
S X Peng,
Z W Liu,
H W Zhao
[show abstract]
[hide abstract]
ABSTRACT: The structure and preliminary commissioning results of a new 2.45 GHz ECR proton ion source and a dual-lens low energy beam transport (LEBT) system are presented in this paper. The main magnetic field of the ion source is provided by a set of permanent magnets with two small electro-solenoid magnets at the injection and the extraction to fine tune the magnetic field for better microwave coupling. A 50 keV pulsed proton beam extracted by a three-electrode mechanism passes through the LEBT system of length of 1183 mm. This LEBT consists of a diagnosis chamber, two Glaser lenses, two steering magnets, and a final beam defining cone. A set of inner permanent magnetic rings is embedded in each of the two Glaser lenses to produce a flatter axial-field to reduce the lens aberrations.
The Review of scientific instruments 02/2012; 83(2):02A329. · 1.52 Impact Factor
-
S Sha,
H W Zhao,
X H Guo,
Z L Zhang,
X Fang,
J W Guo,
W H Zhang,
W Lu,
Y Cao,
H Y Ma, [......],
H Wang,
Q Wu, J Y Li,
Y C Feng,
H Y Zhao,
Y H Zhu,
L T Sun,
X Z Zhang,
X M Chen,
D Z Xie
[show abstract]
[hide abstract]
ABSTRACT: A laser (Nd:YAG laser, 3 J, 1064 nm, 8-10 ns) ion source has been built and under development at IMP to provide pulsed high-charge-state heavy ion beams to a radio frequency quadrupole (RFQ) for upgrading the IMP accelerators with a new low-energy beam injector. The laser ion source currently operates in a direct plasma injection scheme to inject the high charge state ions produced from a solid target into the RFQ. The maximum power density on the target was about 8.4 × 10(12) W∕cm(2). The preliminary experimental results will be presented and discussed in this paper.
The Review of scientific instruments 02/2012; 83(2):02B303. · 1.52 Impact Factor
-
Y Cao,
W Lu,
W H Zhang,
S Sha,
Y Yang,
B H Ma,
H Wang,
Y H Zhu,
J W Guo,
X Fang, [......],
Y C Feng, J Y Li,
H Y Zhao,
H Y Ma,
X Z Zhang,
X H Guo,
Q Wu,
L T Sun,
H W Zhao,
D Z Xie
[show abstract]
[hide abstract]
ABSTRACT: Ion beam transport from the Superconducting Electron Cyclotron Resonance ion source with Advanced design in Lanzhou (SECRAL) electron cyclotron resonance ion source was studied at the Institute of Modern Physics during 2010. Particle-in-cell simulations and experimental results have shown that both space charge and magnetic aberrations lead to a larger beam envelope and emittance growth. In the existing SECRAL extraction beam line, it has been shown that raising the solenoid lens magnetic field reduces aberrations in the subsequent dipole and results in lower emittance. Detailed beam emittance measurements are presented in this paper.
The Review of scientific instruments 02/2012; 83(2):02B726. · 1.52 Impact Factor
-
W Lu,
D Z Xie,
X Z Zhang,
B Xiong,
L Ruan,
S Sha,
W H Zhang,
Y Cao,
S H Lin,
J W Guo, [......],
Q Wu,
H Y Zhao,
B H Ma,
H Wang,
Y H Zhu,
Y C Feng,
J Y Li,
J Q Li,
L T Sun,
H W Zhao
[show abstract]
[hide abstract]
ABSTRACT: A new room temperature electron cyclotron resonance (ECR) ion source, DRAGON, is under construction at IMP. DRAGON is designed to operate at microwaves of frequencies of 14.5-18 GHz. Its axial solenoid coils are cooled with evaporative medium to provide an axial magnetic mirror field of 2.5 T at the injection and 1.4 T at the extraction, respectively. In comparison to other conventional room temperature ECR ion sources, DRAGON has so far the largest bore plasma chamber of inner diameter of 126 mm with maximum radial fields of 1.4-1.5 T produced by a non-Halbach permanent sextupole magnet.
The Review of scientific instruments 02/2012; 83(2):02A328. · 1.52 Impact Factor
-
B. Bartoli,
P. Bernardini,
X. J. Bi,
C. Bleve,
I. Bolognino,
P. Branchini,
A. Budano,
A. K. Calabrese Melcarne,
P. Camarri,
Z. Cao, [......],
L. Zhang,
P. Zhang,
X. Y. Zhang,
Y. Zhang,
Zhaxiciren,
Zhaxisangzhu,
X. X. Zhou,
F. R. Zhu,
Q. Q. Zhu,
G. Zizzi
[show abstract]
[hide abstract]
ABSTRACT: Cosmic ray antiprotons provide an important probe to study the cosmic ray propagation in the interstellar space and to investigate the existence of dark matter. Acting the Earth-Moon system as a magnetic spectrometer, paths of primary antiprotons are deflected in the opposite sense with respect to those of the protons in their way to the Earth. This effect allows, in principle, the search for antiparticles in the direction opposite to the observed deficit of cosmic rays due to the Moon (the so-called “Moon shadow”). The ARGO-YBJ experiment, located at the Yangbajing Cosmic Ray Laboratory (Tibet, P.R. China, 4300 m a.s.l., 606 g/cm2), is particularly effective in measuring the cosmic ray antimatter content via the observation of the cosmic rays shadowing effect due to: (1) good angular resolution, pointing accuracy and long-term stability; (2) low energy threshold; (3) real sensitivity to the geomagnetic field. Based on all the data recorded during the period from July 2006 through November 2009 and on a full Monte Carlo simulation, we searched for the existence of the shadow cast by antiprotons in the TeV energy region. No evidence of the existence of antiprotons is found in this energy region. Upper limits to the p̅ /p flux ratio are set to 5% at a median energy of 1.4 TeV and 6% at 5 TeV with a confidence level of 90%. In the TeV energy range these limits are the lowest available.
Phys. Rev. D. 01/2012; 85(2).
-
B. Bartoli,
P. Bernardini,
X. J. Bi,
C. Bleve,
I. Bolognino,
P. Branchini,
A. Budano,
A. K. Calabrese Melcarne,
P. Camarri,
Z. Cao, [......],
P. Zhang,
X. Y. Zhang,
Y. Zhang,
J. Zhao,
Zhaxiciren,
Zhaxisangzhu,
X. X. Zhou,
F. R. Zhu,
Q. Q. Zhu,
G. Zizzi
[show abstract]
[hide abstract]
ABSTRACT: We report the observation of TeV gamma-rays from the Cygnus region using the
ARGO-YBJ data collected from 2007 November to 2011 August. Several TeV sources
are located in this region including the two bright extended MGRO J2019+37 and
MGRO J2031+41. According to the Milagro data set, at 20 TeV MGRO J2019+37 is
the most significant source apart from the Crab Nebula. No signal from MGRO
J2019+37 is detected by the ARGO-YBJ experiment, and the derived flux upper
limits at 90% confidence level for all the events above 600 GeV with medium
energy of 3 TeV are lower than the Milagro flux, implying that the source might
be variable and hard to be identified as a pulsar wind nebula. The only
statistically significant (6.4 standard deviations) gamma-ray signal is found
from MGRO J2031+41, with a flux consistent with the measurement by Milagro.
01/2012;
-
G. Aielli,
C. Bacci,
B. Bartoli,
P. Bernardini,
X. J. Bi,
C. Bleve,
P. Branchini,
A. Budano,
S. Bussino,
A. K. Calabrese Melcarne, [......],
Jianli Zhang,
L. Zhang,
P. Zhang,
X. Y. Zhang,
Y. Zhang,
Zhaxisangzhu,
X. X. Zhou,
F. R. Zhu,
Q. Q. Zhu,
G. Zizzi
[show abstract]
[hide abstract]
ABSTRACT: The ARGO-YBJ experiment at YangBaJing in Tibet (4300 m a.s.l.) has been
taking data with its full layout since October 2007. Here we present a
few significant results obtained in gamma-ray astronomy and cosmic-ray
physics. Emphasis is placed on the analysis of gamma-ray emission from
point-like sources (Crab Nebula, MRK 421), on the preliminary limit on
the antiproton/proton flux ratio, on the large-scale cosmic-ray
anisotropy and on the proton-air cross-section. The performance of the
detector is also discussed, and the perspectives of the experiment are
outlined.
Nuclear Instruments and Methods in Physics Research Section A Accelerators Spectrometers Detectors and Associated Equipment 12/2011; 661:50. · 1.21 Impact Factor
-
B. Bartoli,
P. Bernardini,
X. J. Bi,
C. Bleve,
I. Bolognino,
P. Branchini,
A. Budano,
A. K. Calabrese Melcarne,
P. Camarri,
Z. Cao, [......],
L. Zhang,
P. Zhang,
X. Y. Zhang,
Y. Zhang,
Zhaxiciren,
Zhaxisangzhu,
X. X. Zhou,
F. R. Zhu,
Q. Q. Zhu,
G. Zizzi
[show abstract]
[hide abstract]
ABSTRACT: Cosmic rays are hampered by the Moon and a deficit in its direction is expected (the so-called Moon shadow). The Moon shadow is an important tool to determine the performance of an air shower array. Indeed, the westward displacement of the shadow center, due to the bending effect of the geomagnetic field on the propagation of cosmic rays, allows the setting of the absolute rigidity scale of the primary particles inducing the showers recorded by the detector. In addition, the shape of the shadow permits to determine the detector point spread function, while the position of the deficit at high energies allows the evaluation of its absolute pointing accuracy. In this paper we present the observation of the cosmic ray Moon shadowing effect carried out by the ARGO-YBJ experiment in the multi-TeV energy region with high statistical significance (55 standard deviations). By means of an accurate Monte Carlo simulation of the cosmic rays propagation in the Earth-Moon system, we have studied separately the effect of the geomagnetic field and of the detector point spread function on the observed shadow. The angular resolution as a function of the particle multiplicity and the pointing accuracy have been obtained. The primary energy of detected showers has been estimated by measuring the westward displacement as a function of the particle multiplicity, thus calibrating the relation between shower size and cosmic ray energy. The stability of the detector on a monthly basis has been checked by monitoring the position and the deficit of the Moon shadow. Finally, we have studied with high statistical accuracy the shadowing effect in the day/”night” time looking for possible effect induced by the solar wind.
Phys. Rev. D. 07/2011; 84(2).
-
The ARGO-YBJ Collaboration,
B. Bartoli,
P. Bernardini,
X. J. Bi,
C. Bleve,
I. Bolognino,
P Branchini,
A. Budano,
A. K. Calabrese Melcarne,
P. Camarri, [......],
L Zhang,
P Zhang,
X Y Zhang,
Y Zhang,
Zhaxiciren,
Zhaxisangzhu,
X. X. Zhou,
F. R. Zhu,
Q. Q. Zhu,
G. Zizzi
[show abstract]
[hide abstract]
ABSTRACT: ARGO-YBJ is an air shower detector array with a fully covered layer of
resistive plate chambers. It is operated with a high duty cycle and a large
field of view. It continuously monitors the northern sky at energies above 0.3
TeV. In this paper, we report a long-term monitoring of Mrk 421 over the period
from 2007 November to 2010 February. This source was observed by the
satellite-borne experiments Rossi X-ray Timing Explorer and Swift in the X-ray
band. Mrk 421 was especially active in the first half of 2008. Many flares are
observed in both X-ray and gamma-ray bands simultaneously. The gamma-ray flux
observed by ARGO-YBJ has a clear correlation with the X-ray flux. No lag
between the X-ray and gamma-ray photons longer than 1 day is found. The
evolution of the spectral energy distribution is investigated by measuring
spectral indices at four different flux levels. Hardening of the spectra is
observed in both X-ray and gamma-ray bands. The gamma-ray flux increases
quadratically with the simultaneously measured X-ray flux. All these
observational results strongly favor the synchrotron self-Compton process as
the underlying radiative mechanism.
06/2011;
-
M. Amenomori,
X. J. Bi,
D. Chen,
S. W. Cui,
Danzengluobu,
L. K. Ding,
X. H. Ding,
C. Fan,
C. F. Feng,
Zhaoyang Feng, [......],
T. Yuda,
H. M. Zhang,
J. L. Zhang,
N. J. Zhang,
X. Y. Zhang,
Y. Zhang,
Yi Zhang,
Ying Zhang,
Zhaxisangzhu,
X. X. Zhou
[show abstract]
[hide abstract]
ABSTRACT: Using the Tibet-III air shower array, we search for steady TeV
γ-rays from 18 pulsars in the Fermi Large Area Telescope pulsar
catalog. Among them, we observe 8 sources including the Crab instead of
the expected 0.41 sources at a significance of 2 σ or more excess.
Under the assumption of Poisson distribution, the chance probability is
estimated to be 1.4×10-8. When the Crab is excluded, it
becomes 1.8×10-7. These low chance probabilities
clearly show that the Fermi pulsars have a statistically significant
correlations with TeV γ-ray excesses.
Astrophysics and Space Sciences Transactions 05/2011; 7:211-215.
-
G. Aielli,
C Bacci,
B. Bartoli,
P. Bernardini,
X. J. Bi,
C. Bleve,
P Branchini,
A. Budano,
S Bussino,
A. K. Calabrese Melcarne, [......],
L Zhang,
P Zhang,
X Y Zhang,
Y Zhang,
Zhaxisangzhu,
Zhaxiciren,
X. X. Zhou,
F. R. Zhu,
Q. Q. Zhu,
G. Zizzi
[show abstract]
[hide abstract]
ABSTRACT: The sun blocks cosmic ray particles from outside the solar system, forming a
detectable shadow in the sky map of cosmic rays detected by the ARGO-YBJ
experiment in Tibet. Because the cosmic ray particles are positive charged, the
magnetic field between the sun and the earth deflects them from straight
trajectories and results in a shift of the shadow from the true location of the
sun. Here we show that the shift measures the intensity of the field which is
transported by the solar wind from the sun to the earth.
01/2011;
-
M. Amenomori,
X. J. Bi,
D. Chen,
S. W. Cui,
Danzengluobu,
L. K. Ding,
X. H. Ding,
C. Fan,
C. F. Feng,
Zhaoyang Feng, [......],
T. Yuda,
H. M. Zhang,
J. L. Zhang,
N. J. Zhang,
X. Y. Zhang,
Y. Zhang,
Yi Zhang,
Ying Zhang,
Zhaxisangzhu,
X. X. Zhou
[show abstract]
[hide abstract]
ABSTRACT: The energy spectrum of cosmic rays around the knee measured by Tibet
air-shower experiment is summarized and its characteristic features are
discussed under two possible scenarios. The result of Tibet experiment
measured over wide range of 1014-1017 eV with high
statistics provided details of the knee at the energy around
4×1015 eV. The study of the chemical composition based
on measurements of proton and helium spectra obtained from air-shower
core detection indicates the dominance of heavy nuclei around the knee.
Such feature can be explained either by contribution of nearby sources
with source composition dominated by heavy nuclei or by nonlinear effect
in diffusive shock acceleration mechanism.
Astrophysics and Space Sciences Transactions 12/2010; 7:15-20.
-
G. Aielli,
P. Camarri,
R. Iuppa,
R. Santonico,
C. Bacci,
P. Branchini,
A. Budano,
S. Bussino,
P. Celio,
M. de Vincenzi, [......],
F. Galeazzi,
R. Gargana,
F. Ruggieri,
C. Stanescu,
P. Galeotti,
E. Giroletti,
G. Liguori,
S. Mastroianni,
E. Rossi,
A. Pagliaro
[show abstract]
[hide abstract]
ABSTRACT: Following the discovery by AGILE (ATEL #2855) and confirmation by
Fermi/Lat (ATEL #2861) of enhanced gamma ray emission from the Crab
Nebula region in the time interval from September 18 to September 22
2010, we report on the observation performed during the same days by
ARGO-YBJ.
The Astronomer's Telegram. 09/2010; 2921:1.
-
G. Aielli,
C. Bacci,
B. Bartoli,
P. Bernardini,
X. J. Bi,
C. Bleve,
P. Branchini,
A. Budano,
S. Bussino,
A. K. Calabrese Melcarne, [......],
Jianli Zhang,
L. Zhang,
P. Zhang,
X. Y. Zhang,
Y. Zhang,
Zhaxisangzhu,
X. X. Zhou,
F. R. Zhu,
Q. Q. Zhu,
G. Zizzi
[show abstract]
[hide abstract]
ABSTRACT: In 2008, the blazar Markarian 421 entered a very active phase and was one of the brightest sources in the sky at TeV energies, showing frequent flaring episodes. Using the data of ARGO-YBJ, a full coverage air shower detector located at Yangbajing (4300 m a.s.l., Tibet), we monitored the source at gamma-ray energies E>0.3 TeV during the whole year. The observed flux was variable, with the strongest flares in March and June, in correlation with X-ray enhanced activity. While during specific episodes the TeV flux could be several times larger than the Crab Nebula one, the average emission from day 41 to 180 was almost twice the Crab level, with an integral flux of (3.6 ± 0.6) × 10–11 photons cm–2 s–1 for energies E>1 TeV, and decreased afterward. This Letter concentrates on the flares that occurred in the first half of June. This period has been deeply studied from optical to 100 MeV gamma rays, and partially up to TeV energies, since the moonlight hampered the Cherenkov telescope observations during the most intense part of the emission. Our data complete these observations, with the detection of a signal with a statistical significance of 3.8 standard deviations on June 11-13, corresponding to a gamma-ray flux about 6 times larger than the Crab one above 1 TeV. The reconstructed differential spectrum, corrected for the intergalactic absorption, can be represented by a power law with an index α = –2.1+0.7 –0.5 extending up to several TeV. The spectrum slope is fully consistent with previous observations reporting a correlation between the flux and the spectral index, suggesting that this property is maintained in different epochs and characterizes the source emission processes.
The Astrophysical Journal Letters 04/2010; 714(2):L208. · 5.53 Impact Factor
-
H W Zhao,
L T Sun,
W Lu,
X Z Zhang,
X H Guo,
Y Cao,
H Y Zhao,
Y C Feng, J Y Li,
H Y Ma,
Y Shang,
B H Ma,
H Wang,
X X Li,
D Z Xie
[show abstract]
[hide abstract]
ABSTRACT: Superconducting electron cyclotron resonance ion source with advance design in Lanzhou (SECRAL) is an 18-28 GHz fully superconducting electron cyclotron resonance (ECR) ion source dedicated for highly charged heavy ion beam production. SECRAL, with an innovative superconducting magnet structure of solenoid-inside-sextupole and at lower frequency and lower rf power operation, may open a new way for developing compact and reliable high performance superconducting ECR ion source. One of the recent highlights achieved at SECRAL is that some new record beam currents for very high charge states were produced by 18 GHz or 18+14.5 GHz double frequency heating, such as 1 e microA of (129)Xe(43+), 22 e microA of (209)Bi(41+), and 1.5 e microA of (209)Bi(50+). To further enhance the performance of SECRAL, a 24 GHz/7 kW gyrotron microwave generator was installed and SECRAL was tested at 24 GHz. Some promising and exciting results at 24 GHz with new record highly charged ion beam intensities were produced, such as 455 e microA of (129)Xe(27+) and 152 e microA of (129)Xe(30+), although the commissioning time was limited within 3-4 weeks and rf power only 3-4 kW. Bremsstrahlung measurements at 24 GHz show that x-ray is much stronger with higher rf frequency, higher rf power. and higher minimum mirror magnetic field (minimum B). Preliminary emittance measurements indicate that SECRAL emittance at 24 GHz is slightly higher that at 18 GHz. SECRAL has been put into routine operation at 18 GHz for heavy ion research facility in Lanzhou (HIRFL) accelerator complex since May 2007. The total operation beam time from SECRAL for HIRFL accelerator has been more than 2000 h, and (129)Xe(27+), (78)Kr(19+), (209)Bi(31+), and (58)Ni(19+) beams were delivered. All of these new developments, the latest results, and long-term operation for the accelerator have again demonstrated that SECRAL is one of the best in the performance of ECR ion source for highly charged heavy ion beam production. Finally the future development of SECRAL will be presented.
The Review of scientific instruments 02/2010; 81(2):02A202. · 1.52 Impact Factor
-
L T Sun,
H W Zhao,
W Lu,
X Z Zhang,
Y C Feng, J Y Li,
Y Cao,
X H Guo,
H Y Ma,
H Y Zhao,
Y Shang,
B H Ma,
H Wang,
X X Li,
T Jin,
D Z Xie
[show abstract]
[hide abstract]
ABSTRACT: Superconducting electron cyclotron resonance ion source with advanced design in Lanzhou (SECRAL) is an all-superconducting-magnet electron cyclotron resonance ion source (ECRIS) for the production of intense highly charged ion beams to meet the requirements of the Heavy Ion Research Facility in Lanzhou (HIRFL). To further enhance the performance of SECRAL, an aluminum chamber has been installed inside a 1.5 mm thick Ta liner used for the reduction of x-ray irradiation at the high voltage insulator. With double-frequency (18+14.5 GHz) heating and at maximum total microwave power of 2.0 kW, SECRAL has successfully produced quite a few very highly charged Xe ion beams, such as 10 e microA of Xe(37+), 1 e microA of Xe(43+), and 0.16 e microA of Ne-like Xe(44+). To further explore the capability of the SECRAL in the production of highly charged heavy metal ion beams, a first test run on bismuth has been carried out recently. The main goal is to produce an intense Bi(31+) beam for HIRFL accelerator and to have a feel how well the SECRAL can do in the production of very highly charged Bi beams. During the test, though at microwave power less than 3 kW, more than 150 e microA of Bi(31+), 22 e microA of Bi(41+), and 1.5 e microA of Bi(50+) have been produced. All of these results have again demonstrated the great capability of the SECRAL source. This article will present the detailed results and brief discussions to the production of highly charged ion beams with SECRAL.
The Review of scientific instruments 02/2010; 81(2):02A318. · 1.52 Impact Factor
